1. Field of the Invention
The present invention relates to antennas of the type used in mobile radio communications and, specifically, to an improved mount for such an antenna.
2. Description of the Prior Art
A variety of antenna configurations are known which utilize flexible members as mounts for mounting the antenna mast upon a support surface. For instance, such mounts are widely used on automobiles, water craft and other motor vehicles. Typical mobile radio communication antennas of the type utilized on automotive vehicles employ "whip" antennas which consist of long conductive rods often made of metal. Whip antennas are conventionally mounted on the support surface of a vehicle by a mount which consists of a base affixed to the vehicle and an external, metal spring in which the lower end of the whip is fastened. The lower end of the external spring is connected to the base and a flexible conductor, usually insulated, is located within the external spring. The flexible conductor extends between the lower end of the antenna whip and means on the base for coupling the conductor to the lead-in cable by which the antenna is connected to the radio set within the vehicle.
In the past, the external, metal spring has consisted of heavy wire wound so as to bulge between its ends. The purpose of the external spring was to permit the antenna rod to fold downwardly at the mount when the upper portion of the rod struck an overhead obstruction which would otherwise bend or break the rod.
Although the external, metal spring has been widely used in whip antennas of the past, certain problems have arisen due to noise generation, particularly where radio frequencies were simultaneously transmitted and received. The external, metal spring was also subject to corrosion and to metal fatigue in use.
As a result, there have been several attempts in the prior art to provide a molded elastomeric body which serves the necessary mechanical functions of allowing the whip to flex while at the same time reducing the DC static associated with the flexing of the external, metal spring. U.S. Pat. No. 2,558,763, to Lee, issued Jul. 3, 1951, shows an antenna mount having a flexible base which includes a plurality of vertically extending spring wires as well as helical spring windings. U.S. Pat. No. 2,668,187, to Von Wald, Jr. et al, issued Feb. 2, 1954, shows a communications antenna with a lead through insulator and a polyethylene sheath. U.S. Pat. No. 4,625,213, to Horn, issued Nov. 25, 1986, shows an antenna mount with a fitting adapted to receive the antenna whip and an opposite fitting adapted to receive a lead-in connector, the fittings being supported by a body formed from a flexible elastomer which provides the sole restoring force to return the whip from the deflected to the upright position.
The present invention has as its object to provide an improved antenna mount which reduces the noise generation created by the flexing of an external, metal wire spring of the type used in prior art whip antennas.
Another object of the invention is to provide an antenna mount having an internal construction capable of providing the restoring force to return the antenna whip from the deflected to the upright position.
Another object of the invention is to provide an antenna mount having an internal construction which eliminates the need for an internal grounding strap of the type used to connect the antenna whip and the lead-in conductor.
Another object of the invention is to provide an antenna mount formed principally from a flexible elastomer to provide improved insulating properties.
Another object of the invention is to provide an antenna mount which is simple in design and economical to manufacture and which is extremely durable in use.
Additional objects, features and advantages will be apparent in the written description which follows.